Many processes are made up of a number of activities which must be performed by different software applications on geographically distributed processing nodes. Such processes often also include steps which must be executed by humans. It would be advantageous to have a process automation system which is capable of running such processes in an automated fashion in a manner which makes efficient use of the resources provided by the distributed processing nodes, and which at the same time satisfies various constraints. It would also be advantageous for such a system to be dynamically configurable at run time, and to permit the "plug and play" of new applications on the processing nodes without effecting previously existing processes.
U.S. Pat. No. 5,535,322 to Hecht, which issued Jul. 9, 1996, entitled "Data Processing System with Improved Work Flow System and Method" describes a system which uses an overall pull system design and an attribute-based file system to store work in progress. The common "pull system" protocol uses DCE (Distributed Computing Environment--a standard from the Open Software Foundation), and each application service pulls work only when it is ready; there is no pushing of work onto an application service. It also does not use an ORB (object request broker) and does not provide the ability for dynamic scheduling.
U.S. Pat. No. 5,627,774 to Schutzman et al which issued May 6, 1997 entitled "Automatic Electronic Messaging System with Feedback and Work Flow Administration" describes an event-driven and conditional rule-based system. The system status reporting or feedback is used for follow-up activity, such as workflow administration or routing. The control in the Schutzman system is centralized, does not use an ORB, and does not provide the ability to extend services at run time.
Also, in Schutzman the feedback information is used for work flow administration, allocating work or tasks in accordance with rules or applications among different queues.
U.S. Pat. No. 5,581,691 to Hsu et al which issued Dec. 3, 1996 entitled "Work Flow Management System and Method" describes a work flow management system and method for executing and tracking the progress of long running work flows, and for recovering from system failures during the execution of long running work flows. The system does not use an ORB bus, but instead uses a static scheduling scheme based on time-outs, and uses a centralized control scheme based on a "Flow" controller that controls the execution of each work flow. In terms of recovery, the Hsu system logs records and output event signals, stored in a history database, to ensure the recovery of a work flow upon a system failure.
U.S. Pat. No. 5,301,320 to McAtee which issued Apr. 5, 1994 entitled "Work Flow Management and Control System" describes an approach to the creation of large application systems by representing workflow tasks in a fully modular fashion that allows the designer to alter the order and relationships among tasks without the reconfiguration of the entire workflow system. The system can integrate various types of application software, and is capable of partitioning tasks among various operators, computers and computer terminals as specified by the designer. This integration is not done using an ORB bus; and is not object-oriented, and does not have dynamic features such as dynamic scheduling.
U.S. Pat. No. 5,630,069 to Flores which issued May 13, 1997 entitled "Method and Apparatus for Creating Workflow Maps of Business Processes" describes a method and system which provides consultants, business process analysts, and application developers with a unified tool with which to conduct business process analysis, design, and documentation. The fundamental concept of workflow analysis is that any business process can be interpreted as a sequence of basic transactions called workflows. The workflow system uses client/server design and concentrates workflow operations in the workflow server rather than the end user applications.
In addition to the above described patent literature regarding workflow systems, there are several existing commercially available work flow management software products.
One such product entitled "Action Workflow Enterprise Series" developed by Action Technologies does not support dynamic scheduling, does not use an ORB bus, and does not support the WPDL (Workflow Process Definition Language) of the WfMC (Workflow Management Coalition). It only focuses on human centred workflows. In addition, since the modelling elements for the organizational embedding are not very expressive (only roles and identities), complex rules of responsibility cannot be modelled at all.
A system entitled "COSA" from the German software company Software-Ley is built according to the client/server paradigm, does not use an ORB, and does not provide dynamic scheduling of processes. COSA's modelling elements are dedicated to model human organizations, not "organizations" of servers, machines and cells which might be useful in manufacturing environments. The only data types supported in COSA are files and unstructured variables. Data flow of structured data between activities cannot be specified.
Another WFM system, FlowMark, from IBM is a database centred workflow management system. It does not use an ORB bus, does not support dynamic scheduling, does not support runtime extension of services, and does not support dynamic upgrades to notification policies. FlowMark follows the client/server paradigm. The only way to execute a FlowMark process without human intervention is to declare program or process activities as automatic.
InConcert from XSoft uses standard services like RPC (remote procedure call), NFS (network file system) and database, and does not use an ORB bus. InConcert is distributed over a heterogeneous network according to a client/server architecture. It does not support dynamic scheduling and does not extend workflow services at run time.
Finally, SAP Business Workflow from SAP AG is a database centred WFM system which uses R/3 to provide an enterprise with standard functionality for information processing. SAP Business Workflow is integrated into R/3 and not a stand-alone system.